.img{
  img{
    width: 100px;
    height: 100px;
    min-height: 100px;
    position: relative;
  }
  img:after {
    content: url(http://www.baidu.com/img/baidu_jgylogo3.gif);
    display: block;
    color: rgb(100, 100, 100);
    position: absolute;
    top:0px;
    left: 0px;
    width: 100%;
  }
}
.height{
  width: 100px;
  height: 200px;
  background-color: #ccc;
  .content{
    width: 100%;
    height: 50%;
    padding-top: 25%;
    padding-bottom: 25%;
    background-color: #000;
  }
}